disable sweep button without balance

public/views/paperWallet.html

@@ -59,7 +59,7 @@
        </div>
 
       <button 
-        ng-disabled="paperWallet.sending"
+        ng-disabled="paperWallet.sending || paperWallet.balanceSat <= 0"
         ng-style="{'background-color':index.backgroundColor}" 
         class="button black round expand" 
         ng-click="paperWallet.sweepWallet()" 

src/js/controllers/paperWallet.js

@@ -15,7 +15,7 @@ angular.module('copayApp.controllers').controller('paperWalletController',
       self.isPkEncrypted = (data.charAt(0) == '6');
     }
 
-    self.scanFunds = function() {
+    self._scanFunds = function(cb) {
       function getPrivateKey(scannedKey, isPkEncrypted, passphrase, cb) {
         if (!isPkEncrypted) return cb(null, scannedKey);
         fc.decryptBIP38PrivateKey(scannedKey, passphrase, null, cb);
@@ -34,80 +34,77 @@ angular.module('copayApp.controllers').controller('paperWalletController',
         return true;
       }
 
+      getPrivateKey(self.scannedKey, self.isPkEncrypted, $scope.passphrase, function(err, privateKey) {
+        if (err) return cb(err);
+        if (!checkPrivateKey(privateKey)) return cb(new Error('Invalid private key'));
+
+        getBalance(privateKey, function(err, balance) {
+          if (err) return cb(err);
+          return cb(null, privateKey, balance);
+        });
+      });
+    }
+
+    self.scanFunds = function() {
       self.scanning = true;
       self.privateKey = '';
+      self.balanceSat = 0;
       self.error = '';
+
       $timeout(function() {
-        getPrivateKey(self.scannedKey, self.isPkEncrypted, $scope.passphrase, function(err, privateKey) {
+        self._scanFunds(function(err, privateKey, balance) {
           if (err) {
             $log.error(err);
-            self.error = 'Could not get private key';
+            self.error = err.message || err.toString();
-            self.scanning = false;
+          } else {
-            return;
+            self.privateKey = privateKey;
-          }
+            self.balanceSat = balance;
-          if (!checkPrivateKey(privateKey)) {
-            self.error = 'Invalid private key';
-            self.scanning = false;
-            return;
-          }
-          self.privateKey = privateKey;
-
-          getBalance(privateKey, function(err, balance) {
-            self.scanning = false;
-            if (err) {
-              $log.error(err);
-              self.error = 'Could not get balance';
-              self.scanning = false;
-              return;
-            }
             var config = configService.getSync().wallet.settings;
             self.balance = profileService.formatAmount(balance) + ' ' + config.unitName;
-            $timeout(function() {
+          }
-              $scope.$apply();
+
-            }, 1);
+          self.scanning = false;
-          });
+          $timeout(function() {
+            $scope.$apply();
+          }, 1);
         });
       }, 100);
     }
 
+    self._sweepWallet = function(cb) {
+      addressService.getAddress(fc.credentials.walletId, true, function(err, destinationAddress) {
+        if (err) return cb(err);
+
+        fc.buildTxFromPrivateKey(self.privateKey, destinationAddress, null, function(err, tx) {
+          if (err) return cb(err);
+
+          fc.broadcastRawTx({
+            rawTx: tx.serialize(),
+            network: 'livenet'
+          }, function(err, txid) {
+            if (err) return cb(err);
+            return cb(null, destinationAddress, txid);
+          });
+        });
+      });
+    };
+
     self.sweepWallet = function() {
       self.sending = true;
       self.error = '';
+
       $timeout(function() {
-        addressService.getAddress(fc.credentials.walletId, true, function(err, destinationAddress) {
+        self._sweepWallet(function(err, destinationAddress, txid) {
           if (err) {
+            self.error = err.message || err.toString();
             $log.error(err);
-            self.error = 'Could not get destination address';
-            self.sending = false;
-            return;
           }
-
+          self.sending = false;
-          fc.buildTxFromPrivateKey(self.privateKey, destinationAddress, null, function(err, tx) {
+          $timeout(function() {
-            if (err) {
+            $scope.$apply();
-              $log.error(err);
+            if (!err) go.walletHome();
-              self.error = 'Could not build transaction';
+          }, 1);
-              self.sending = false;
-              return;
-            }
-
-            fc.broadcastRawTx({
-              rawTx: tx.serialize(),
-              network: 'livenet'
-            }, function(err, txid) {
-              if (err) {
-                $log.error(err);
-                self.error = 'Could not broadcast transaction';
-                self.sending = false;
-                return;
-              }
-
-              $timeout(function() {
-                $scope.$apply();
-              }, 1);
-              go.walletHome();
-            });
-          });
         });
       }, 100);
-    };
+    }
   });